


The Night is Still Young

by Benzaldehyde



Category: Undertale (Video Game)
Genre: Alphyne, Alphynecentric, Established Relationship, F/F, First time using strap-on, Fluff, Or more like alfiiiine amiright?
Language: English
Status: Completed
Published: 2015-12-25
Updated: 2015-12-25
Packaged: 2018-05-09 08:49:34
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,954
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5533622
Author URL: https://archiveofourown.org/users/Benzaldehyde/pseuds/Benzaldehyde
Summary: <blockquote class="userstuff">
              <p>Undyne had a good idea how she wanted to spend the evening and she was hoping Alphys wasn't too tired to be game as well.</p><p>Undyne was feeling particularly mischievous, she was going to play with her food tonight.</p><p>Alphys however has other ideas.</p>
            </blockquote>





	The Night is Still Young

Today was the best day.

This was the day of the week that Alphys and Undyne always promised for each other.

This restful day of the week was always most welcome to both of them. Alphys enjoying the moment to leave the worries of the lab on the door-step and Undyne to to leave the protection of the royal family in the royal guards very capable hands.

This was originally just a one off when Alphys was pushed nearly to the breaking point when half the electricity grid in the underground shorted out and she had spent 2 days solid to find and fix the fault. They both soon discovered they really enjoyed spending time eating junk food, watching terrible TV and doing it all in their pajamas together. There was a intimacy to the act, wordlessly enjoying each others company while clad in cuddle combat gear and presiding over the carefully assembled pillow fort on the couch.

It was good to be queen of this magnificent plush kingdom for two.

The evenings entertainment was a re-run as there was little much else for their viewing pleasure. Lazily half watching the human cop show and half surfing the net on her cell phone; Undyne had Alphys bundled up in her lap and was lazily tracing shapes around the scutes on the back of the scientists head. Gazing down Undyne took in the sight of her sleepily blissing out to the light touches, nails lightly grazing the textures of tough scale or gently sinking into the softer skin in between.

She loved seeing Alphys like this, someone who is usually flitting between either socially anxious or bending over backwards to help others FINALLY being able to ditch their reservations and relax. This was a sight that was all for Undyne, a gift that she considered of up-most importance and she greedily defended it. The first time seeing Alphys like this while having one of their movie date nights cemented the decision to offer her girlfriend to move in with her; she wanted to take care of her the way she deserved. Feeling a bubble of pride welling up, Undyne had a good idea how she wanted to spend the evening and she was hoping Alphys wasn't too tired to be game as well.

Undyne was feeling particularly mischievous, she was going to play with her food tonight.

After the cellphone had been quietly switched off (because no way was she in the mood to be interrupted, sorry Papyrus) she diverted her full attention to the lounging lizard sprawled across her legs; the first plan of attack was to get Alphys a little more awake.

Now with both hands free Undyne got to work with having one hand still tracing over the larger scales jutting from Alphys' scalp while the other began slowly caressing down her side to her hip, the thin cotton of her pyjamas meaning that the touch and heat would we well felt.

Alphys shifted and sighed contentedly, Undyne discovered the sensitivity of Alphys' sides when their relationship started becoming physical in nature. The areas that were less scale and more skin were prime areas to get lavished with attention in order to get the scientist very hot and bothered. Undyne shifted her left hand to begin to carefully scratch Alphys' neck and jawline, the very tips of her claws barely toughing the skin which was very quickly heating up as a result of her ministrations, a distinct blush beginning to creep up through the yellow skin.

Taking advantage of her flexibility Undyne lowered her head to begin languidly peppering gentle kisses over Alphys' brow. Between the hand rubbing her side and the shower of kisses, Alphys was beginning to be roused from her light snoozing, occasionally letting out more contended sighs and hums. Undyne took this as a signal to go in for the kill and began to mix in possessive squeezes to the hand on the side and grazing her teeth against the larger scutes. The sighs became louder and the hums were quickly becoming more like small moans; eventually Alphys was very much awake and propped herself up in Undynes lap to face her.

“...Hey...” the guard purred.

“...Hey...” replied the scientist, looking a little dishevelled with their half lidded eyes and lopsided grin. She squared herself properly into Undynes lap so she was straddling her and began threading her small fingers though the warriors hair.

She loved playing with Undynes hair, on particularly bad days where she would come home excessively tense after a gruelling day of work and would sit and methodically mico-braid all of Undynes hair (the hardest part being to get Undyne to sit still that long, though they quickly learned that the end result would look amazing). This evening her hair was its natural shiny smooth red gorgeousness, much easier for threading Alphys' tiny clawed hands through to scratch the scalp.

This earned her a breathy sigh and a delicate quiver of Undynes fins, despite the best efforts to be 'in control' the fins always gave her away; they flare when she's excited or angry, fold down when relaxed and this quiver currently on display went with either attentive curiosity or arousal. The light flush surfacing along the tops of the fins indicated the latter and in this state they were incredibly sensitive, but playing with them will be saved for later. Alphys had cottoned onto Undynes intentions and certainly welcomed them, but there was a severe lack of smooching going on right now.

Alphys leaned up and finally planed a firm and wanting kiss on Undynes mouth, this was tenderly returned with the added bonus of feeling a pair of webbed hands gently holding her hips. The kissing quickly became more heated, the hand in Undynes hair gabbed a fist full and gently pulled eliciting a groan that Alphys took full advantage of to deepen the kiss, her mouth sliding against Undynes. The warriors eyebrows raised in surprise; this was a possessive side to Alphys that she had never seen before and it caused a flush that started from her collar bones all the way to the top of her fins. A mix of confusion and lust rocked through her; equal parts 'what?' and 'wow' as her mind was now rushing through all the possibilities. She may have forgotten to breathe.  
  
“A-Are you OK?” the researcher whispered against her lips.

Undyne was snapped back out of her stupor to see a mildly concerned expression peering at her.

“Never better.” she murmured, punctuated with a soft peck to the reptiles short snout. “Shall we take this to the bedroom?”

The scientist giddily shifted and hummed in agreement, she pressed into the lean frame in front of her leaning up to hungrily kiss along the guards jawline. Undyne was still taken aback by the amount of gusto being displayed, but this only served to excite her further as she playfully slapped both hands on Alphys rear to steady her. The indignant squawk and giggle that resulted was music to her ears as she stood up and stumbled with an arm full of amorous girlfriend wrapped around her waist while searching with the other hand for the light switch. Light made navigating the dark corridor much faster as she reached the end and opened the door to the bedroom, once over the threshold she kicked it shut with little bit more force than necessary, she had much more enticing matters to attend to.

  
She gently placed Alphys on the bed and crawled right after her; all toothy grin, sly smile and fins fully flared; predator stalking her prey. Alphys felt a shiver run through her spine, _fuck_ Undyne knew exactly how seductive she looked when she did that. A pair of demanding hands began to creep up under the hem of her shirt ghosting over her sides as a trail of soft kisses began ascending up the exposed skin. The researcher took the clue to lean forward to have her shirt removed all the while reaching forward to stroke along her girlfriends back to pinch and pull up the bottom of the obstructing black vest top.

Now on an even playing field and both topless Alphys pulled Undyne flush on top of her to resume the kissing they had started in front of the TV. She carefully palmed up the sides of the warrior careful not to press too hard on the sensitive gills. She could feel the shiver of the lean body above her, heat radiating off all the tight and lean muscle that was always savoured being cold blooded. Undyne sank into the soft body below her as her whole world condensed down to the precious sensations all over her. She wanted more. She lapped against the lips pressed to hers gently pleading. The gesture was returned with passion, a hot moan escaping as tongues glided against each other. She inched her hands lower to squeeze a handful of the plump thy as she began to rock against her.

It wasn't long before the room was filled with the sound of desperate moaning and panting accented with wet kisses. They untangle themselves briefly to get their breath back and to remove the last articles of clothing they had on, Alphys needing a little extra help getting the briefs over her tail. The scientist then reached up and removed the warriors eye patch, revealing the permanently shut eye marred with a set of light blue scars; a ritual that has become a routine since living together, the patch was placed gently on the night stand.

“W-w-wait a sec sweetie” said Alphys, just as Undyne was about to push her back on the bed.

“Y-yeah?” she replied, her quivering fins drooping slightly in concern.

“I...I thought we might try something new t-tonight so uh, if you don't mind waiting here a m-moment” Alphys then crouched down and pulled out a small plain box from under the bed looking a little nervous. While clutching the box she crawled back onto the bed and back into Undynes lap, once fully seated she opened the package.

There was a little confusion at first, at first sight it looked like a bundle of leather straps and buckles nestled in the thin tissue packing paper but then nestled amongst them was a purple phallu-...

...oh...

... _OH_...

Undynes wide eye darted from the box to her girlfriends face, who was looking thoroughly embarrassed and then back to the box. She knew exactly what this was, she had seen a video of a couple using one of these on the internet. She watched the video from start to finish, enraptured by the sight of a very hot and heavy scene of two humans very much enjoying themselves. The thought of having her lover underneath her, doing those things to her... _oh fuck_.

She reached in with one hand and curiously pressed against the toy, the material was slightly textured and had a lot of give- probably silicone.

“Oh? When did you get this?” she whispered softly into Alphys ear as she tangled her hands in the harness to lift it out.

“I-I had been thinking a-about it for a while... I bought it t-today”

Imagining the poor girl who was anxious on a normal day working up enough courage to 1. walk into a sex shop 2. browse a display of all shapes and sizes (though more likely she would have done this online before going) to then 3. Purchase the strap-on made Undyne feel a little guilty, but Alphys being able to put aside her personal demons to do this was something special.

She turned and began to tenderly kiss the side of the reddening snout next to her. Trying to calm down her stammering girlfriend before she blew a gasket. She went to coax the researcher back underneath her until-

“I wanna wear it!” blurted out of the blue.

...oh...

... _OH_...

Alphys was being full of surprises this evening and once again left the guard with her jaw dropping and forgetting how to breathe.

She could picture it. She wanted it. Remembering and realising the promise in the hair-pulling incident from earlier. She _needed_ it.

She grabbed Alphys by the hips and hoisted her up to standing next to bed and immediately got to work with getting that harness on the curvy waist in front of her. She fumbled with one buckle as she planed hot kisses on a soft belly; her hands were shaking a little. Alphys started to fix the other side while adjusting it, she was able to find one that was made for monsters with tails witch made it much more comfortable and stable. This was going better than she planned, she partly expected this as her partner seems to enjoy everything they had done together so far but seeing Undyne this excited filled her with … determination.

Now that the equipment was firmly in place Undyne dragged the scientist on top of her to lay down on the bed for another round of incredibly noisy kissing, feeling the firmness pressed against her hip. She devolved into a whining wreck after long, kisses becoming more like gasps and nips which meant she wasn't just ready... she was _really_ ready.

Alphys was able to disentangle herself to lean back and view her handiwork, a very dishevelled and needy looking sight indeed. She noticed the faint nervousness in her partners face.

“Are you ok sweetie? We d-dont have to if you do-”

“No way” the guard reassured, stroking the back of her hand down her partners arm. “I...I just never done this kind of thing before, but I really want this, with you”. She pushed herself up on her hands to plant a firm kiss on the scientists mouth.

“Ok” she replied and pecked the warriors cheek. After a little thought she decided how to make this the most enjoyable for both of them.

“Turn around” she cooed, making a very deliberate hand gesture.

Undyne shakily turned over onto her hands and knees, her muscles were having a really hard time co-ordinating. The scientist loved looking at the athlete before her, all lean muscle, steel under skin, she could watch her move for hours. She leaned forward and placed a gentle hand on Undynes shoulder and trailed it back, listing the muscles as she went over the trapezius, the rhomboideus major, the latissimus dorsi, and finally to one of her favourites.... She trailed her fingers over the ass she had been presented with and down further to the wetness, an interesting shade of pink in contrast to the blue skin. She carefully pressed her thumb over it only to have Undyne hum and press back into the contact. She pressed in a little deeper, gauging how ready her partner was, something had her very riled up, she was already hot and wanting.

After a little psyching herself up she felt that Undyne had waited long enough she leant forward and started to guide the tip in. She was careful, not that the one she purchased was excessively large but more that she didn't think that anything bigger than fingers have been beyond this point. She pressed forward a little, waited, pressed forward a little more. The small whimpers and moans were encouraging that what she was doing was good, she rubbed and kissed that gorgeous back she loved so much. Eventually her hips came to be flush against Undynes rear, she took a moment to observe, the sight was amazing. Undynes hair was was spilled over the sheets, hands were gripping into the linen and she was trembling all over trying to control her breathing, willing her body to relax to the foreign feeling. Her eyes opened and met with Alphys, she wanted more, she pressed back to make her point clear.

This new sensation was unusual, the strange feeling of fullness made her think that what was inside her was reaching deeper. She was mainly used to attention being given with either fingers or tongue (and _damn_ did Alphys have a tongue). The textures were pleasant enough and she could feel herself reacting, becoming more sensitive; but there was something that she knew was close...but not quite there.

The first few thrusts were a little unsure and shaky, trying to find that right angle.

“... _Ah_...lemme just move my legs a little” breathed Undyne as she moved her legs further apart.

The next press that came almost knocked the wind out of her.

Woah.

“Hunnnnnnn, oh, right there” she moaned now gripping the sheets even tighter.

Alphys took no time in gaining confidence and was now building a rhythm to the strokes, her hands firmly gripping those amazing hips and pulling them back to meet her. Her eyes raked over the view before her and the sound of skin slapping on skin and a very vocal girlfriend was definitely the most erotic experience she had ever had. This was better than she ever imagined, hoping that her partner would indulge in a fantasy of hers was one thing, but seeing how much it was _wrecking_ Undyne, she was a _mess_. She could feel the muscles under hands flex and shudder as her girlfriend tried to reign in some of her strength as she pressed back, she was covered in a light perspiration and her fins were visibly trembling.

“Ah...ahn... _oh fuck_...alph... _aah_ ”

Undynes breathing was becoming more and more erratic as a hand reached under to rub at herself, she was so close.

Suddenly, Alphys felt the body in front of her tense up and let out a crescendoing string of loud curses and moans. She continued to rock into the warmth while massaging her partners hips, whispering soft praises into her back.

“w-wow...holy...you're _amazing...thank you_ ”

Once the shuddering beneath her subsided she carefully eased out and gently rolled the warrior over. Both were out of breath and were sporting very strong blushes, before Alphys could collapse on top of her for some much deserved smooching she felt a firm hand on her arm and another diving down between them.

“ _Mmm_...more”

 _Oh...oh wow_...

She slid in easily though she did notice a slight wince from her partner, she must still be a little sensitive. Alphys shuffled forward on her knees a little to get closer, as amazing as what they did a moment ago was she thinks maybe something a little more tender was called for. She pressed their bodies together and kissed her languidly, they put their arms around each other and just stayed that way for a moment, just enjoying the sensation of their cooling bodies. As the two began to warm up again their hands began to roam, the researchers ghosting over Undynes gills making her shiver, whereas Undynes hands had a very decided prize in mind. She grazed her claws gently down Alphys' back and grasped the base of her tail, this was another sensitive spot she discovered on their previous encounters.

The researcher had not anticipated this. She arched back with a gasp and bucked her hips forward, this new angle felt much closer and a seam in the harness was pulling in _just_ the right way.

The movement was more placid, more about enjoying each other as it was enjoying the sensations. They kissed, they praised each other, their hands began to wander again, they moved together. Undyne arched and wrapped her legs around the leather clad waist and hissed at the new feeling of being penetrated deeper. Right when Alphys doesnt think Undyne could get any hotter she gets proven wrong again, seeing Undynes legs wrapped around her and the flex of that well toned abdomen as she met with every thrust and her hands were fisting in the sheets either side of her head... She couldn't keep this steady control for long.

The strokes became more frantic, blindly bucking forward just needing a little more friction. The guards attempts at keeping with the rhythm were waning, the two now just rubbing together in a frenzy of sensation and high pitch moaning. Alphys could feel that familiar heat coiling and burning deliciously within her, she looked down and could see that gorgeous face tossed to one side, a little overwhelmed by all the sensations. They were both bordering that climax, but Alphys wasn't going to last much longer. Taking action she reached up and threaded her fingers through that red beautiful hair and pulled.

The reaction was dazzling, the sudden sensual gasp and the bending of Undynes back was nothing short of obscene. With the last of what was left of her rationality the scientist grazed her teeth along the delicate fins to then drop her head and sink them lightly into her partners collarbone.

The entirety of the warriors body thrashed, the air rushed out of her lungs and she could feel her very core rhythmically clamp down on the toy inside her. The pressure and sensations became a heady mix as all she could do was bury her face into her partners neck and hold on as she rode out the orgasm.

The fierce climax didn't go unnoticed by Alphys, she was done for.

She surrendered to the tingling she could feel all over her, hips battling to keep moving but proving difficult as her nurons began to randomly fire off. Her eyes squeezed shut as the thrumming in the back of her skull took over. Her lovers name on her tongue as she buried into the bosom below her.

They stayed that way for what felt like the longest time, perspiring and trying to catch their breath. After a few moments Undyne had to request Alphys to move, having the full weight of another person still settled on their pelvis was starting to become sore. The sudden feeling of emptiness made her gasp as Alphys leant back on her haunches and unclipped the strap-on. After casting the device to one side the scientist collapsed next to her partner, cooling off while gazing into each others eyes.

"...Wow..."

"You can say that again"

Alphys scooted closer and rested her head into the juncture of the warriors arm, they always ensured they talked after they tried out anything new in the bedroom. Then again they just liked talking out their feelings, there was no keeping secrets between the two of them.

"So..." Said the scientist "How was that for yo-" she was suddenly cut off by a very deep kiss.

"Holy fuck that was amazing, it was a little...intense. But I never knew that I could feel that good. I totally want to do that again"

"That's good to hear, I had a lot of fun too, seeing you like that, you were so wild...and that you wanted to keep going even after youd-"

"Well, all that possessiveness kinda turned me on...a lot. I didn't think I was into hair stuff until you did it"

"O-oh, well that's good to know"

"But next time I want to try it out"

"I...wh....gah...." Speech suddenly became incomprehensible for the scientist.

"I can't believe you can be bashful now after what we just did you dork. Pretty sure if we had neighbours the whole street would've known what we just did" she hugged her partner in closer and planted a sweet kiss on her brow. "Is that a yes?"

"Y-yeah".

"Good" she affirmed as she pulled the covers over the two and wrapped her arms around her partner "We can skip gym tomorrow if you want to make good on that promise, that was quite a work-out".

"Oh, my God!"

 

**Author's Note:**

> Hello wonderful readers!
> 
> This is my first ever try at writing, I hope you enjoyed it! I was going to save this for when I got back home but I was overcome with Christmas cheer!
> 
> This is for all the wonderful people who fill my tumblr dash with beautiful fishwives, I love you guys.
> 
> Merry Christmas sinners!


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